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B. H. INGEBRIGTSEN 1,337,363

APPARATUS TO CONTROL HEARING Filed Dec. 16, 1950 Patented Dec. 22, 1931 UNITED STATES PATENT OFFICE BRYNJ'ULF HAY INGEBRIGTSEN 03 08110, NORWAY APPARATUS TO CONTROL HEARING Application filed December 16, 1980, Serial No. 502,666, and in. Norway November 14, 1928.

The present invention has for its object.

an apparatus which is adapted to be used instead of the usual whispering test for con trolling hearing.

In accordance with the invention there is utilized as control source of sound a narrowair outlet opening, which is connected with an air vessel for gradually varying pressure. At the outlet through the said opening or jet the air produces a whizzing sound, the strength of'which varies in proportion to the pressure, and by means of a pressure gauge on the air vessel or on the conduit from the said air vessel to the outlet opening it is consequently possible to ascertain the hearing faculty as a numeric value.

The air outlet jet or opening is located in the ear cap, so that the the opening will always be at the same distance from the ear, and the air current may either be directed away from the ear through an opening in the exterior wall of the cap or against a thin diaphragm mounted in the ear cap between the outlet opening and the ear.

Two forms of the invention niatically indicated on the drawings.

On Fig. 1, 1 is a. vessel containingair under pressure and connected with some suitable source of pressure by means of a tube 2 30 with valve or cook 3. The pressure in the vessel is indicated by means of a pressure gauge 4.

The vessel has an outlet opening 5, which is connected by means of a flexible tube 6 with a tube 7, terminating in a narrow outlet jet or opening 8. Said outlet opening 8- is located at the apex of an open conical ear cap 9 provided with a soft tightening edge 10 01 rubber sponge, felt or the like.

When the apparatus is to be used for investigating purposesa predetermined pressure is established in vessel 1, and ear cap 9 is applied against the ear which is to be investigated. The pressure in vessel 1. at which the whizzing sound from the air outlet opening 8 cannot longer be heard, will then give a numerical indication of the hearing faculty.

On Fig. illustrated.

2 another form of the ear cap is In this form the outlet jet or opening 8 directs the current of air against a diaphragm 11 located between the opening 8 and the annular contact member 10, which is applied against the ear to be investigated.

I claim:

1. Ap aratus for ascertaining the hearing faculty y a numerical indication, characterized. by the combination with a pressure vessel for air with gradually varying pressure of an air pressure gauge and an ear cap provided with a narrow air jet for producing a whizzing sound and a flexible tube for connecting said air vessel with said jet.

2. Apparatus as claimed in claim 1, characterized by the fact that the ear ca is provided with a diaphragm, against wiioh the current of air is directed and which is located between the ear and the air 'et.

, In testimony whereof I a 1: my signature.

BRYNJULF HAY INGEBRI'GTSEN.

are diagram- 7 

